For the convenience and ease of dispensing, products are very often sold in pump packages. These packages comprise a container for the product and a pump for dispensing the product from the container. The basic function of most pumps is based on displacement of the product. Valves open and close in order to transfer product from a reservoir to the point of application. Most pumps share the same construction principles in that they have a central reservoir that collects and holds the product for dispensing, and a piston within the reservoir which provides a passageway to the dispensing point. The piston is the main component that pressurizes the product within the reservoir before dispensing.
The general sequence of functions to dispense product from a pump is as follows: With the pump on a container, and the container filled with the product to be dispensed, the first action is depression of the actuator of the pump. This moves the piston, which is attached to the actuator, down into the reservoir, compressing the product within the reservoir. The compressed product lifts a top valve within the piston, allowing the product to pass out of the actuator. As the actuator and piston return to the starting position, a vacuum is formed in the reservoir which closes the top valve. As the vacuum increases, a bottom valve, at the base of the reservoir, opens allowing the product to be pulled into the reservoir from the container. The continual opening and closing of the valves, under compression and vacuum, pushes the product through the system. By design, the flow of the product is in one direction, pulling product up into the reservoir, and then displacing it out through the actuator.
Because the product is pulled from the container, thereby decreasing the amount of product within the container, a vacuum is created within the container. If this vacuum is allowed to build up, the pump ceases to function at the point where the vacuum within the container equals the force required to pull the product into the reservoir. Therefore, at the time the bottom valve opens to fill the reservoir with product, a passageway opens between the container and the outside atmosphere. This passageway allows the vacuum within the container to dissipate so that the contents within the container can be kept at the same pressure as that of the outside atmosphere, thereby never allowing a vacuum pressure to be reached which would cease pump function. This process is known as "venting" and allows oxygen to enter into the container to equalize the pressure.
Products that contain labile components, such as fragrances, biologically active materials, fats, oils, or any other components that react with oxygen, tend to have their characteristics change over time with exposure to oxygen. This happens because certain components of the product degrade when exposed to oxygen. That is, when the product contacts the air, the labile component oxidizes and changes character, e.g., either by a loss of activity, or an alteration in odor or appearance. When products are placed within a container with a venting pump, the product is continually exposed to oxygen as the product is dispensed. This presents a particular problem when the product contains one or more labile components. Over time, this continual exposure to the air causes the labile component of the product to oxidize, thus changing the characteristics of that product.
The present invention provides a dispensing system that assists in preventing the oxidation of biologically active components of a product.
The present invention further provides a dispensing system that will not interfere with package aesthetics.
Also, the present invention provides a dispensing system that is inexpensive to manufacture.
Further, the present invention provides a dispensing system that is simple for a consumer to operate.